neodymium magnet,magnet. a): D3-280mm. b): Grade reach N52, N38EH. c): Coating: Ni, Zn, Silver, Gold, passivation ... . neodymium magnet,ndfeb magnetic material,magnet.a): Size Φ3----Φ280mmb): Grade cover N33-N52, N30M-N50M , N30H-N48H, N30SH-N45SH, N28UH ...